1. Field of the Invention
The invention relates to electrical cabling. More particularly, the invention relates to reducing cross-talk in electrical cabling.
2. Description of the Related Art
Within electrical cable such as that used in a local area network (LAN), the reduction of crosstalk remains an ongoing problem for the communication industry. Conventionally, within an electrical cable that typically contains a plurality of twisted pair of individually insulated conductors such as copper wires, many configurations and techniques have been implemented to reduce crosstalk between the respective electrically conducting pairs.
For example, one of the most useful techniques for reducing crosstalk within electrical cabling includes separating parallel and adjacent transmission lines. In this manner, numerous components such as spacer elements have been included in the electrical cable to maintain sufficient spacing between the conducting pairs and thus reduce cross-talk therebetween. See, U.S. Pat. Nos. 4,920,234 and 5,149,915.
Because typical communications industry electrical cables include four twisted pair, many spacer element configurations comprise one or more centrally-located spacer elements, such as a dielectric flute, with the twisted pairs arranged in various configurations therearound. See, e.g., U.S. Pat. Nos. 5,132,488 and 5,519,173.
However, these conventional cable arrangements aimed at reducing crosstalk often are burdened with other problems. For example, existing spacer elements are relatively inflexible and thus restrict movement of the twisted pairs within the electrical cable. Also, existing spacer elements are relatively expensive and difficult to handle and manipulate during the electrical cabling manufacturing process.
Accordingly, it would be desirable to have an electrical cabling apparatus and method for making that addresses the aforementioned concerns.
The invention is embodied in an electrical cable apparatus and method for making. The electrical cable apparatus comprises a plurality of paired conductive elements, a dielectric jacket formed around the plurality of paired conductive elements, and at least one dielectric film separating the pairs of conductive elements within the dielectric jacket. For example, for an arrangement having four twisted pair of copper wires within an electrically insulating jacket, embodiments of the invention include two dielectric films surrounding alternating pairs of individually insulated conductor elements. Alternatively, embodiments of the invention include a dielectric film formed helically between individual conductive elements within the conductor pairs. The dielectric film is made of one or more of the following materials: ethylchlorotrifluoroethylene (ECTFE or HALAR(copyright)), poly(vinyl chloride) (PVC), polyolefins, and fluoropolymers including fluorinated ethylene-propylene (FEP or TEFLON(copyright)), perfluoroalkoxy polymers of tetrafluoroethylene and either perfluoropropyl ether (PFA) or perfluoromethylvinyl ether (MFA). Alternatively, the dielectric film is made of woven glass yarn tape such as KAPTON(copyright). The dielectric film has a width, e.g., of approximately 0.125 to 0.250 inch and a thickness, e.g., of approximately 0.002 to 0.020 inch (2 to 20 mils).
According to embodiments of the invention, a method for making an electrical cable comprises providing a plurality of the paired conductive elements, forming the dielectric jacket around the conductor pairs, and forming the dielectric film around one or more of the conductor pairs. Alternatively, the method comprises providing a plurality of the paired conductive elements, forming the dielectric jacket around the conductor pairs, and forming the dielectric film helically between the individual conductors within one or more conductor pairs. The thin dielectric film provides separation between conductor pairs and/or between individual conductors within conductor pairs to reduce crosstalk therebetween.